Shaped the world? Depend which part of the world you mean. Britain, for all that it conquered territories in the far east, did not have that much impact there outside Australia and NZ, and perhaps India.
However I think even Rome or britain have very unequal shaping scores. If you count largest amount of land heavily influenced, britain is probably a top contender. But if you consider population, considering the massive population of the Asian world where England didn't do much shaping of the world - they just occupied it for a while - then China is a major contender as well.
Personally I think no nation can claim to have truly shaped THE World even in slight amounts. They can claim to have shaped *a* world, but there are more than one world on this planet - I see this planet divided in about four great worlds, with many minor "side tribes".
1)The Western World. Rome being the obvious primary influence. It's possible to divide this further in a Latin world (Spain, Med Europe and ex-colonies) and a Germanic world (North Europe, England and ex-full colonies*) - the differences between the two are in great part readily noticeable.
*IE, Australia, NZ, US, Canada as opposed to India, SE Asia et al - colonies SETTLED by them as opposed to colonies where they just took over the administration.
2)The Islamic World. The primarily influence there, well, you have one guess as to which it could possibly be. It starts with "Arabia" and ends the same.
3)The Eastern World. China being the definite great influence there, and India the other major player. If I were to draw east-west parallels I would compare India to Egypt/Persia/Fertile Crescent and China to the Greco-Roman powers.
When you get right down to it, England, despite its great impact on the Western World (or Rome, for that matter), didn't have all that much of a deep, lasting impact on the Eastern World - not really that much more than the Eastern World had on the west. Sure, industrialization had a great impact on the east - but then so did paper on the west. And China, for all the impact it had in the East, cannot claim to have impacted the western or islamic world any more deeply than the west impacted the east.
Perhaps if one day we have something that we can refer to as a "human world" with no such distinction then it will be possible to designate a nation as having a greater impact on the world than any before. I just don't see that as really possible at present - because you have to judge which part of the world is most important, and then to quantify the impact of each state on each nation (or should that be each individual?) - which gets ridiculous aplenty.